c - 为什么我的矩阵没有相加？

Question

当我添加矩阵时，添加的矩阵输出只是零，而不是添加的数字。我的老师说问题可能是我将总和作为双指针而不是三重指针传递来更新它，但我不知道如何修复它。我该怎么做才能得到矩阵数字的和而不是零？

#include <stdio.h>

#include <stdlib.h>



int** make_matrixA(int num_rows, int num_cols){
int** matrixA;
int row, col;
int userNum;


    matrixA = (int**)malloc(num_rows * sizeof(int*));
for(row = 0; row < num_rows; ++row){
    matrixA[row] = (int*)malloc(num_cols * sizeof(int));
}
for(row = 0; row < num_rows; ++row){
    for(col = 0; col < num_cols; ++col){
        scanf("%d", &userNum);
    }
}
return matrixA;
}

int** make_matrixB(int num_rows, int num_cols){
int** matrixB;
int row, col;
int userNum;


    matrixB = (int**)malloc(num_rows * sizeof(int*));
for(row = 0; row < num_rows; ++row){
    matrixB[row] = (int*)malloc(num_cols * sizeof(int));
}
for(row = 0; row < num_rows; ++row){
    for(col = 0; col < num_cols; ++col){
        scanf("%d", &userNum);
    }
}
return matrixB;
}

int** make_matrixC(int num_rows, int num_cols){
int** matrixC;
int row;


    matrixC = (int**)malloc(num_rows * sizeof(int*));
for(row = 0; row < num_rows; ++row){
    matrixC[row] = (int*)malloc(num_cols * sizeof(int));
}
return matrixC;
}


int** add_matrix(int num_rows, int num_cols, int** matrixA, int** matrixB, int** matrixC){
int row, col;

for(row = 0; row < num_rows; ++row){
    for(col = 0; col < num_cols; ++col){
        matrixC[row][col] = matrixA[row][col] + matrixB[row][col];
    }
}
return matrixC;
}

void print_matrix(int num_rows, int num_cols,int** matrixA, int** matrixB, int** matrixC){
int row, col;

printf("A + B = \n");
for(row = 0; row < num_rows; ++row){
    for(col = 0; col < num_cols; ++col){
        matrixC[row][col] = matrixA[row][col] + matrixB[row][col];
        printf("%d ", matrixC[row][col]);
    }
    printf("\n");
}
}

void delete_matrixA(int num_rows, int** matrixA){
int row;
for(row = 0; row < num_rows; ++row){
    free(matrixA[row]);
}
free(matrixA);
}

void delete_matrixB(int num_rows, int** matrixB){
int row;
for(row = 0; row < num_rows; ++row){
    free(matrixB[row]);
}
free(matrixB);
}

void delete_matrixC(int num_rows, int** matrixC){
int row;
for(row = 0; row < num_rows; ++row){
    free(matrixC[row]);
}
free(matrixC);
}

int main(){
int num_rows, num_cols;
int** matrixA;
int** matrixB;
int** matrixC;  

//get input
printf("Please enter the number of rows: ");
scanf("%d", &num_rows);
printf("Please enter the number of columns: ");
scanf("%d", &num_cols);     

//make matrix A
printf("Enter Matrix A\n");
matrixA = make_matrixA(num_rows, num_cols);

//make matrix B
printf("Enter Matrix B\n");
matrixB = make_matrixB(num_rows, num_cols);

//add the matrices
matrixC = make_matrixC(num_rows, num_cols);
matrixC = add_matrix(num_rows, num_cols, matrixA, matrixB, matrixC);

//print the matrix
print_matrix(num_rows, num_cols, matrixA, matrixB, matrixC);

//delete the matrices
delete_matrixA(num_rows, matrixA);
delete_matrixB(num_rows, matrixB);
delete_matrixC(num_rows, matrixC);

return 0;
}

Answer 1

你的make_matrix()函数不好。读取数字的代码

for(row = 0; row < num_rows; ++row){
    for(col = 0; col < num_cols; ++col){
        scanf("%d", &userNum);
    }
}

你应该这样做

for(row = 0; row < num_rows; ++row){
    for(col = 0; col < num_cols; ++col){
        scanf("%d", &matrixA[row][col]); //use matrix to store number
    }
}

适本地更改您的函数以使用正确的变量。 如果没有这个，您的代码不会将值存储在矩阵中，并将矩阵中的随机数相加。