http://www.daniweb.com – Hey DaniWeb. I am getting stuck in an infinite loop when I input a character instead of an integer during a scanf("%d"....); I know this is because C doesn't provide any built in error checking. I know I can fix this by using getchar() in place of scanf, and changing my variable to a character, then converting it to an int, but it would make my life alot simpler if there were another way around this. Can anyone give me some help please? Code: #include<stdio.h> #include<stdlib.h> #include <math.h> struct T_vector { float *data; int size; } vector1, vector2; struct T_Matrix{ struct T_vector row[3]; } matrix1, matrix2; //------------------------------------------------------------------------------ // print matrix 1 function below // -> prints off the contents of matrix 1 void print_matrix1(){ int i=0,j=0; for(j=0;j<3;j++){ printf("["); for(i=0;i<3;i++){ printf("%6.2f ",matrix1.row[j].data[i]); } printf("]\n"); } } //------------------------------------------------------------------------------ // print matrix 2 function below // -> prints off the contents of matrix 2 void print_matrix2(){ int i=0,j=0; for(j=0;j<3;j++){ printf("["); for(i=0;i<3;i++){ printf("%6.2f ",matrix2.row[j].data[i]); } printf("]\n"); } } //------------------------------------------------------------------------------ // print menu function below // -> simply prints the options void printmenu(){ printf("\n\ (1)Enter vector 1.\n\ (2)Enter vector 2.\n\ (3)Enter 3x3 matrix 1.\n\ (4)Enter 3x3 matrix 2.\n\ (5)Find magnitude of vector.\n\ (6)Normalize the vector.\n\ (7)Find dot product of vector 1 and 2.\n\ (8)Find the inverse matrix.\n\ (9)Transpose a matrix.\n\ (10)Find product of matrix 1 and 2.\n\ (11)Quit\n\n"); } //------------------------------------------------------------------------------ // magnitude function below // ->accepts a pointer to a vector and it's size float magnitude(float *vector, int size){ int i; float mag = 0, square=0; for(i=0;i<size;i++){ square += vector[i]*vector[i]; } mag = sqrt(square); return mag; } //------------------------------------------------------------------------------ //normalize function below // -> accepts a pointer to a vector and it's size int normalize(float *vector, int size){ int i; float mag = magnitude(vector, size); if(mag==0) return 1; for(i=0;i<size;i++)vector[i]=vector[i]/mag; return 0; } //------------------------------------------------------------------------------ // transpose function below void transpose(struct T_Matrix *matrix){ int i, j, temp_matrix[3][3]; printf("Tran"); for(i=0;i<3;i++){ printf("["); for(j=0;j<3;j++)printf("%6.2f ",(*matrix).row[i].data[j]); if(i==0)printf("] = ["); else printf("] ["); for(j=0;j<3;j++)printf("%6.2f ",(*matrix).row[j].data[i]); printf("]\n "); } for(i=0;i<3;i++){ for(j=0;j<3;j++)temp_matrix[j][i]=(*matrix).row[i].data[j]; } for(i=0;i<3;i++){ for(j=0;j<3;j++)(*matrix).row[i].data[j]=temp_matrix[i][j]; } } //------------------------------------------------------------------------------ // dot product function below float dot_product(float *vector1, float *vector2, int size){ int i; float dot=0; printf("\n\n"); for(i=0;i<size;i++){ dot = dot+vector1[i]*vector2[i]; } return dot; } //------------------------------------------------------------------------------ // multiply function below void multiply(struct T_Matrix *matrix3, struct T_Matrix *matrix4){ int i, j, k; float temp_matrix[3][3]={{0,0,0},{0,0,0},{0,0,0}}; for(i=0;i<3;i++){ for(j=0;j<3;j++){ for(k=0;k<3;k++){ temp_matrix[i][j]=temp_matrix[i][j]\ +(*matrix3).row[i].data[k]*(*matrix4).row[k].data[j]; } } } for(i=0;i<3;i++){ printf("["); for(j=0;j<3;j++)printf("%6.2f ",(*matrix3).row[i].data[j]); if(i==1)printf("] x ["); else printf("] ["); for(j=0;j<3;j++)printf("%6.2f ",(*matrix4).row[i].data[j]); if(i==1)printf("] = ["); else printf("] ["); for(j=0;j<3;j++)printf("%6.2f ",temp_matrix[i][j]); printf("]\n"); } for(i=0;i<3;i++){ for(j=0;j<3;j++){ (*matrix3).row[i].data[j]=temp_matrix[i][j]; } } } //------------------------------------------------------------------------------ // inverse function below int inverse(struct T_Matrix *matrix){ int i=0, j=0, k=0; // loop controls float det=0, mat[3][3]={0,0,0,0,0,0,0,0,0}; // temp store the matrix float inv[3][3]={0,0,0,0,0,0,0,0,0}; // temp. store the inverse matrix for(i=0;i<3;i++){ for(j=0;j<3;j++){ mat[i][j] = (*matrix).row[i].data[j]; } } // This is where I calculate the determinate of a 3x3 matrix det += mat[0][0]*(mat[1][1]*mat[2][2]-mat[1][2]*mat[2][1]) \ - mat[0][1]*(mat[1][0]*mat[2][2]-mat[1][2]*mat[2][0]) \ + mat[0][2]*(mat[1][0]*mat[2][1]-mat[1][1]*mat[2][0]); if(det==0){ // error checking for determinate printf("Error. Matrix has no inverse."); return 1; } // This is where I calculate the inverse inv[0][0]=(mat[1][1]*mat[2][2]-mat[1][2]*mat[2][1])/det; inv[0][1]=(mat[0][2]*mat[2][1]-mat[0][1]*mat[2][2])/det; inv[0][2]=(mat[0][1]*mat[1][2]-mat[0][2]*mat[1][1])/det; inv[1][0]=(mat[1][2]*mat[2][0]-mat[1][0]*mat[2][2])/det; inv[1][1]=(mat[0][0]*mat[2][2]-mat[0][2]*mat[2][0])/det; inv[1][2]=(mat[0][2]*mat[1][0]-mat[0][0]*mat[1][2])/det; inv[2][0]=(mat[1][0]*mat[2][1]-mat[1][1]*mat[2][0])/det; inv[2][1]=(mat[0][1]*mat[2][0]-mat[0][0]*mat[2][1])/det; inv[2][2]=(mat[0][0]*mat[1][1]-mat[0][1]*mat[1][0])/det; // Here, I copy it back to the passed in matrix for(i=0;i<3;i++){ for(j=0;j<3;j++)(*matrix).row[i].data[j]=inv[i][j]; } // Printing off the desired output printf("\nInv"); for(i=0;i<3;i++){ printf("["); for(j=0;j<3;j++)printf("%6.2f ",mat[i][j]); if(i==0)printf("] = ["); else printf("] ["); for(j=0;j<3;j++)printf("%6.2f ",(*matrix).row[i].data[j]); printf("]\n "); } return 0; } //------------------------------------------------------------------------------ // main below int main(){ int i, j, command; float dotproduct; // loop controls, command var.s and dotprod. float mag_vector1, mag_vector2; // var.s for the magnitudes start: // I use this to restart the program i=0, j=0, command=dotproduct=0; // I reset the variables each iteration mag_vector1=mag_vector2=0; printmenu(); // to print / reprint the menu printf("\n\n"); printf("Please enter the number of the command: "); scanf("%d",&command); fflush(stdin); switch(command){ case 1: printf("\nNote: Non-numerical characters will be accepted as 0."); printf("\nHow long is vector 1?"); scanf("%d",&vector1.size); vector1.data = calloc(vector1.size, sizeof(float)); for(i=0;i<vector1.size;i++){ printf("Enter the value in position %d: ",i); scanf("%f",&vector1.data[i]); fflush(stdin); } printf("\n\n"); break; case 2: printf("Note: Non-numerical characters will be accepted as 0."); printf("\nHow long is vector 2?"); scanf("%d",&vector2.size); vector2.data = calloc(vector2.size, sizeof(float)); for(i=0;i<vector2.size;i++){ printf("Enter the value in position %d: ",i); scanf("%f",&vector2.data[i]); fflush(stdin); } printf("\n\n"); break; case 3: printf("Note: Non-numerical characters will be accepted as 0."); matrix1.row[0].data = calloc(3,sizeof(float)); for(i=0;i<3;i++){ printf("\nEnter # at row 1 column %d: ",i+1); scanf("%f",&matrix1.row[0].data[i]); fflush(stdin); } matrix1.row[1].data = calloc(3,sizeof(float)); for(i=0;i<3;i++){ printf("\nEnter # at row 2 column %d: ",i+1); scanf("%f",&matrix1.row[1].data[i]); fflush(stdin); } matrix1.row[2].data = calloc(3,sizeof(float)); for(i=0;i<3;i++){ printf("\nEnter # at row 3 column %d: ",i+1); scanf("%f",&matrix1.row[2].data[i]); fflush(stdin); } print_matrix1(); printf("\n\n"); break; case 4: printf("\nNote: Non-numerical characters will be accepted as 0."); matrix2.row[0].data = calloc(3,sizeof(float)); for(i=0;i<3;i++){ printf("\nEnter # at row 1 column %d: ",i+1); scanf("%f",&matrix2.row[0].data[i]); fflush(stdin); } matrix2.row[1].data = calloc(3,sizeof(float)); for(i=0;i<3;i++){ printf("\nEnter # at row 2 column %d: ",i+1); scanf("%f",&matrix2.row[1].data[i]); fflush(stdin); } matrix2.row[2].data = calloc(3,sizeof(float)); for(i=0;i<3;i++){ printf("\nEnter # at row 3 column %d: ",i+1); scanf("%f",&matrix2.row[2].data[i]); fflush(stdin); } print_matrix2(); printf("\n\n"); break; case 5: i=0; // set i so it can be used as command choice printf("Find magnitude for vector 1 or 2: "); scanf("%d",&i); // choose input if(i==1){ //calculate magnitude mag_vector1 = magnitude(vector1.data, vector1.size); //print off correct output printf("\n\n|["); for(i=0;i<vector1.size;i++)printf("%.2f ",vector1.data[i]); printf("]| = %.2f\n",mag_vector1); } else if(i==2){ //calculate magnitude mag_vector2 = magnitude(vector2.data, vector2.size); // print off correct output printf("\n\n|["); for(i=0;i<vector1.size;i++)printf("%.2f ",vector1.data[i]); printf("]| = %f\n",mag_vector2); } else { printf("\nError. Not a valid input.\n"); break; // check for correct input } printf("\n\n"); break; case 6: printf("Normalize vector 1 or 2: "); // Ask which one? scanf("%d", &i); if(i==1){ // print off beginning printf("\n\nnorm["); for(i=0;i<vector1.size;i++)printf("%.2f ",vector1.data[i]); printf("] = ["); // do calculations normalize(vector1.data, vector1.size); // print second half for(i=0;i<vector1.size;i++)printf("%.2f ",vector1.data[i]); printf("]\n\n"); } else if(i==2){ // print off beginning printf("\n\nnorm["); for(i=0;i<vector2.size;i++)printf("%.2f ",vector2.data[i]); printf("] = ["); // do calculations normalize(vector2.data, vector2.size); // print second half for(i=0;i<vector2.size;i++)printf("%.2f ",vector2.data[i]); printf("]\n\n"); } else printf("\nError. Improper input.\n\n"); printf("\n\n"); break; case 7: if(vector1.size!=vector2.size){ // must be equal size for dot product printf("Error. Vectors not of equal size."); break; } dotproduct = dot_product(vector1.data,vector2.data,vector1.size); // print off the correct formatted output printf("\n["); for(i=0;i<vector1.size;i++) printf("%.2f ",vector1.data[i]); printf("]dot["); for(i=0;i<vector2.size;i++) printf("%.2f ",vector2.data[i]); printf("] = %f",dotproduct); printf("\n\n"); break; case 8: // run inverse function inverse(&matrix1); printf("\n\n"); break; case 9: i=0; // clear i so it can be used as command variable printf("Transpose matrix 1 or 2? "); scanf("%d",&i); if(i==1){ printf("\n\n"); transpose(&matrix1); // pass in matrix1 to inverse function printf("\n\n"); } else if(i==2){ printf("\n\n"); transpose(&matrix2); // pass in matrix2 to inverse function printf("\n\n"); } else { printf("\nError. Improper input.\n\n"); break; } printf("\n\n"); break; case 10: printf("\n\n"); multiply(&matrix1,&matrix2); printf("\n\n"); break; case 11: goto End; // jump past 'goto start' printf("\n\n"); break; default: printf("\nError. Improper input.\n\n"); printf("\n\n"); break; } goto start; End: // free all allocated variables free(vector1.data); free(vector2.data); free(matrix1.row[0].data); free(matrix1.row[1].data); free(matrix1.row[2].data); free(matrix2.row[0].data); free(matrix2.row[1].data); free(matrix2.row[2].data); return 0; } (General)
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