How can i minimize the number of test expressions in if statements?

So i have 4 variables that i need to check in order for my program to work, it gets to 16 test expressions in one if statement if hard coded. How could i minimize it ? The only way i thought of going was boolean algebra and i was very wrong. Anyone have any suggestions or something i would appreciate. The function is something like a printf function.

string = form("%d %s %f %lf %c", 1, "ASA", 4.12345, 1.123421, 'A');


char * form(char * format, ...){

char * result = (char *)calloc(1, 1), val_int[12], * val_str, * pos_int, * pos_str, val_double[12], * pos_double, * pos_char, * pos_float, val_float[12];
va_list arguments; va_start(arguments, format);

do
{
    pos_int = strstr(format, "%d"); pos_str = strstr(format, "%s"); pos_double = strstr(format, "%lf"); pos_float = strstr(format, "%f"); pos_char = strstr(format, "%c");

    if(pos_int && (pos_int < pos_str && pos_int < pos_float && pos_int < pos_double && pos_int < pos_char))
    {
        sprintf(val_int, "%d", va_arg(arguments, int));
        result = (char *)realloc(result, strlen(val_int) + strlen(result) + (pos_int - format) + 1);

        strncat(result, format, pos_int - format);
        strcat(result, val_int);
        format = pos_int + 2;
    }
    else if(pos_str && ( pos_str < pos_int && pos_str < pos_float && pos_str < pos_double && pos_str < pos_char))
    {
        val_str = va_arg(arguments, char *);
        result = (char *)realloc(result, strlen(val_str) + strlen(result) + (pos_str - format) + 1);

        strncat(result, format, pos_str - format);
        strcat(result, val_str);
        format = pos_str + 2;
    }
    else if(pos_double && (pos_double < pos_float && pos_double < pos_char && pos_double < pos_str && pos_double < pos_int))
    {
        sprintf(val_double, "%lf", va_arg(arguments, double));
            result = (char *)realloc(result, strlen(val_double) + strlen(result) + (pos_double - format) + 1);

        strncat(result, format, pos_double - format);
        strcat(result, val_double);                     
        format = pos_double + 3;
    }
    else if(pos_float && (pos_float < pos_int && pos_float < pos_double && pos_float < pos_str && pos_float < pos_char))
    {
        sprintf(val_float, "%f", (float)va_arg(arguments, double));
        result = (char *)realloc(result, strlen(val_float) + strlen(result) + (pos_float - format) + 1);

        strncat(result, format, pos_float - format);
        strcat(result, val_float);
        format = pos_float + 2;
    }
    else if(pos_char && (pos_char < pos_int && pos_char < pos_str && pos_char < pos_float && pos_char < pos_double))
    {
        char val_char[2] = "\0";
        val_char[0] = (char)va_arg(arguments, int);
        result = (char *)realloc(result, strlen(val_float) + strlen(result) + (pos_float - format) + 1);

        strncat(result, format, pos_float - format);
        strcat(result, val_float);
        format = pos_float + 2;
    }
}while(pos_int || pos_str || pos_double || pos_float || pos_char);

va_end(arguments);

result = (char *)realloc(result, strlen(result) + strlen(format) + 1);
strcat(result, format);
return result; }

In these if statements is only one test expression besides the first which just sees if the main variable for the testing is initialized, and i need to do another 15 for making every possible situation for each if statement.