如何編寫會返回一個字符串在C

Question

如何從函數返回一個字符串的函數：

char * temp; 

int main() 
{ 
    temp = malloc(129); 

    double g_symbol_b_amount = 8536.700000; 
    printf("\n value: %s\t ", format_double_trans_amount(double g_symbol_b_amount)); 
} 

char *format_double_trans_amount(double amount) 
{ 
    char amount_array_n1[25]; 
    strcpy(amount_array_n, ""); 
    sprintf(amount_array_n, "%1f", amount); 
    temp = amount_array_n; 
    return temp; 
} 

這裏我得到的值：0.000000
我需要的原單值，請幫我這個？

Answer 1

我測試過下面的代碼並正確行爲。你能確認嗎？

#include "stdio.h" 
#include "stdlib.h" 

char * temp; 

char *format_double_trans_amount(double amount) 
{ 
    sprintf(temp,"%1f",amount); 
    return temp; 
} 

int main() 
{ 
    double g_symbol_b_amount = 8536.700000; 
    temp = (char*) malloc(sizeof(char) * 129); 
    printf("\n value: %s\n", format_double_trans_amount(g_symbol_b_amount)); 
    free(temp); 
} 

Answer 2

你printf()格式字符串應該有%s而不是%f因爲傳遞的值（從format_double_trans_amount返回的值）是一個char *而不是double。

我想你也應該改變你的format_double_trans_amount()功能：

char *format_double_trans_amount(double amount) 
{  
    sprintf(temp,"%1f",amount); 
    return temp; 
}