So i have to write a calculator program that
a.entering the letter q quits (i got this part)
b.if more than one character is added into the opperator return an error message and give another chance (i think i need to use a char buf[80] and then state that
if (char[2]!='\n'){ continue;})
c.if a user enters an operator when a number is expected tell them to enter another number(i have no idea)
d. add an "n" opperator that skips entering a value for the second number and causes doOp to set acc to the negative value(i got this part)
e.add an s opperator that stores the 1st number entered (i think i did the correctly)
f. add a p opperator to set op to '+'. thus adding together the stored number and the new number meaning adding the new acc to the stored one. (i attempted and it doesnt work but i dont really understand how to do this)

Any help would be greatly appreciated!

#include<stdio.h>
#include<ctype.h>
float mem;
float doOp(int op, float num1, float num2, float memory, float acc);
int main(int argc, char * argv[]) {
	int c;
	float num,acc;
	char quit;
	

printf("ECE 15 Assignment 3 \n");											// Print: ECE 15 Assignment 3
printf("Cristina Zepeda\n\n");												// Print: Names of partners; end each name with \n
printf("Welcome to Calculator\n\n\n");										// Greeting
	
	while(1) {
		printf("Enter number:");											// Get number
		scanf("%f",&acc) || scanf ("%c", &quit);
		if (quit == 'q'){ 													//checking for q to quit
			printf("Calculator exiting\n");
			break;
	}
			printf("The number into acc is %f\n",acc);  						//prints the enter value onto the screen
		while(1) {														// Loop until clear
			printf("Enter op:");
			do c = getchar(); while(isspace(c));							// Get op
			printf("The op char is:%c\n",c);
		
		if(c)
		if(c=='q') {														// if q is entered then quit
				printf("Calculator exiting\n"); 
				return 0;
			}
		if (c=='n'){
				goto answer;
			}											// skips entering num and goes to answer
		if (c=='s'){
				goto stored;
			}											// stores acc to mem										
		if (c=='p'){
				printf("Calculator exiting\n");  ;
			}											// skips entering num and goes to answer
		else if (c != '+' && c != '-' && c != '*' && c != '/' && c != 'n' && c != 's' && c != 'p') { 						// Checks to make sure opperation is acceptable
			printf ("Error! invalid opperator. Please enter +, -, *, /, n, s, or p\n");
				continue;
	}
			printf("Enter another number:");							
			scanf("%f",&num) || scanf ("%c", &quit);						// Get number num
		if (quit == 'q'){ 													//checking for q to quit
			printf("Calculator exiting\n");
			return 0;
	}
			printf("Number into num is: %f\n",num);			
	answer: {	
			acc = doOp(c, acc, num, mem, acc);									// Perform op
			printf("The answer is:");										// Display answer
			printf("%f\n\n\n",acc);
	stored: {
			printf("\n\n\n");{
				break;
	}
		} 
			}
		
	
		}
			}
	return 0;
}


float doOp(int op, float num1, float num2 , float memory, float acc){
	switch (op) {
		case '+' : return num1 + num2;
			break;
		case '-' : return num1 - num2;
			break;
		case '*' : return num1 * num2;
			break;
		case '/' : return num1 / num2;
			break;
		case 'n' : return 0 - acc;
			break;
		case 's' : return mem=acc;
			break;
		case 'p' : return acc+mem;
			break;
		default: return num1;
		
			}
	}
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